Purpose: :
Many ganglion cells exhibit push–pull interactionswhereby excitation increases as inhibition decreases in responseto a flash. Our lab has found similar interactions in most conebipolar cells and amacrine cells. Here we describe the commonfeatures of this interaction in all three cell–types andinvestigate its functional role.

Methods: :
Rabbit retinal neurons were whole–cell patch–clampedin sliced and flat–mounted retinas to record excitation,inhibition and voltage. Ganglion cells were also loose–patchedfor spike recordings. Stimuli included flashes of +/–100% contrast, sinusoids, gratings and modulated sinusoids.Spatial stimuli were used only in flat–mount on ganglioncells. We perfused tissue with 10µM strychnine or 100µMpicrotoxin in Ames’ medium.

Results: :
Most bipolar, amacrine and ganglion cell subtypes respondedto a light flash with either increased excitation accompaniedby a reinforcing decrease in inhibition or decreased excitationreinforced by increased inhibition. This reinforcement betweenexcitation and inhibition was maintained for sinusoidal stimuliover a wide range of frequencies (0.3Hz–15Hz). Synaptic rectification at many synapses distorted excitatoryand inhibitory inputs to retinal neurons. This distortion mixedthe high– and low–frequency components of signalsso that changes in contrast for rapidly changing signal wereindistinguishable from changes in baseline brightness in bothtime and space. Push–pull interactions between excitationand inhibition suppressed this distortion, resulting in a responsethat more accurately represented the structure of complex stimuli.

Conclusions: :
Push–pull interactions appear in a majorityof bipolar, amacrine and ganglion cells. This interaction compensatesfor distortion generated by the inherently nonlinear synapsesat every stage of processing so as to maintain an accurate representationof the visual world.